PHILADELPHIA (CBS) — A convicted serial rapist was sentenced to prison today for his knifepoint attacks on four women in Kensington in late 20111.

Marcos Camacho, 32, was been sentenced to what almost certainly amounts to a life sentence — 50 to 100 years in prison — for three rapes and one attempted rape (see previous story).

Prosecutors noted that the victims were especially vulnerable: all four were drug addicted, and three were prostitutes.

In his sentencing, Judge Charles Ehrlich noted that the victims lived in the shadows, and said that Camacho made it even darker for them.

Prosecutor Jack O’Neill says the defendant showed a devotion to doing wrong in a way that showed no concern for other people.

“He held a knife to their throat, he raped them, and threw them out into the winter cold, naked. He did it over and over again in a small period of time, and he did it with no remorse at all,” O’Neill told reporters.

Camacho denied the charges at trial, but the jury rejected his testimony, and again at sentencing he claimed he was the victim of injustice.